The present invention relates generally to maintenance of large scale recirculating water systems. In particular, the present invention provides a method and apparatus for removal of accumulated sand, silt, detritus, algae and other debris from golf course recirculating water and irrigation systems. A related application of the invention is for maintenance of recirculating water systems used, for example, in ponds, water fountains and decorative pools.
Typical golf course recirculating sprinkler systems will pump 750,000 to 2,500,000 gallons per night during the warm season through a system of 2,000 to 2,400 sprinkler heads. Most golf courses are designed so that lakes or water hazards are primary storage reservoirs for the sprinkler systems. A golf course lake or water hazard functioning as a primary storage reservoir will typically have an intake positioned near the bottom of the reservoir. A gravity feed line or a pump will transfer water from the water reservoir to a “wet well.” The “wet well” is typically a concrete lined structure which serves as a secondary reservoir, from which one or more large pumps will pump water to the sprinkler heads. A pump house is normally built over each “wet well.” A typical golf course will have from 1 to 4 primary reservoirs, each of which has its own “wet well.” A typical “wet well” will have 1 to 4 separate pumps pumping water from it to the sprinkler system.
Most golf courses use what is known as “tertiary cleansed” (also referred to as recycled) water, as opposed to potable water. The tertiary cleansed (or recycled) water is supplied by a local water district and typically introduced into the primary storage reservoir or reservoirs. The economics of using recycled water on a golf course can be quite profound. The cost of recycled water is typically 40% of the cost of potable water available from a municipal water supply. A typical golf course saves approximately $2,000 per day during the warm season by utilizing recycled water as opposed to potable municipal water.
The problem with existing recirculating water systems for golf courses is that over time, detritus, golf balls, algae and all manner of debris accumulate in the water and on the bottom of the water hazard or lake that is used as the primary reservoir for the sprinkler system. In addition, algae in many situations tends to collect around the grating used on typical existing water intakes. To make matters worse, sand, silt and other fine particulate matter over time tends to enter the intake and become entrained in the water pumped through the pumping station and throughout the sprinkler lines of the entire golf course. The financial ramifications of allowing this process to continue unabated can be catastrophic. For example, if a water hazard acting as a primary reservoir has to be cleaned, the prior art systems typically require the golf course operator to close down operation of the golf course and drain the water hazard acting as the primary reservoir. Machines such as backhoes or loaders then enter the drained water hazard and remove the accumulated detritus and other debris such as twigs, golf balls, rocks, etc. During this process, it is not unusual for rather serious damage to be caused to the turf around the water hazard acting as the primary reservoir due to the access required by the rather heavy machines that must enter the drained water hazard. The cost of draining and cleaning a water hazard can run from $300,000 to $500,000. In addition to these out-of-pocket expenses, the golf course operator often suffers the additional expense of shutting down the golf course as well as expense of replacing turf and vegetation that dies while the irrigation system is closed down. Some golf courses may remain open by using the more expensive potable water (if available) and paying the increased cost.
In addition to the cost of cleaning a water hazard acting as a pimary reservoir for the irrigation system, additional expensive damage may be caused to the pumping system and sprinkling system by the unabated accumulation of detritus and other debris allowed to enter the pumping and sprinkling system. For example, sand or algae that is allowed to enter the sprinkler system can require the replacement of all sprinkler heads at a cost of appoximately $250,000. In addition to the replacement cost of sprinkler heads, there are additional costs of turf and vegetation which dies as a result of fouled sprinkler heads. A further complication is that some fouled sprinkler heads remain open and cause localized flooding. Localized flooding can require shutdown of a portion of or the entire golf course. Additional damage may be done to the large pumps utilized to supply water from the “wet wells” to the sprinkler system and to pumps transferring water from the primary reservoir into the “wet well” or secondary storage reservoir. Typical golf courses have one or more pump stations, each of which utilizes a total of 1 to 4 pumps. Replacement of one of those pumps costs approximately $85,000 plus shutdown time. Another danger in those installations where pumps are used to transfer water from the water hazard/primary reservoir to the “wet well” is that the screens at the intake become clogged with algae and the pumps cavitate. The cavitation can cause the pumps to burn out, requiring their replacement.
Many of the above problems described for typical golf course recirculating sprinkler systems are also experienced in systems which recirculate water in ornamental pools, water fountains, ponds and the like. Those systems typically involve intakes positioned in a primary reservoir and pumping systems which pump water from the intake either through fountains, waterfalls or transfer water to a higher level from whence it flows back to the primary reservoir. The typical cleanup of an ornamental pool whose recirculating water system has become fouled by sand, detritus and other debris is similar to that required for golf courses. The owner must shut the system down, drain the primary reservoir, remove the sand, detritus and other debris, refill the system with water and replace any vegetation that has died during the process.
According to the present invention, a method and apparatus are provided for remediation of recirculating water systems that have begun to accumulate sand, detritus, algae and other debris in the intake system and pumping stations. The present invention also provides a relatively low cost preventive maintenance system which, when utilized periodically, avoids the dangerous buildup of sand, detritus and other debris, all without violating the integrity of the surroundings and without disrupting operation of the golf course or fountain or decorative pool involved.
According to the present invention, a portable system has been developed which can readily be delivered to the shore of a water hazard/primary reservoir in a lightweight truck. The apparatus includes a hydraulically actuated vacuum nozzle, preferably having a three inch diameter intake line. This vacuum intake is carried into the water hazard/primary reservoir by a qualified diver. The diver moves the hydraulic vacuum nozzle to and fro and the nozzle sucks up the sediment and debris around the region of the water system intake. The vacuum nozzle also completely removes any algae or other matter adhering to and tending to block the water system intake. The sediment and debris flow upwardly through the nozzle and through an eductor system wherein the eductor nozzle is fed by water pumped directly from the water hazard/reservoir into the eductor. The entrained sediment and debris and water are pumped into a temporary, permeable dam which has been erected on the shore of the water hazard/reservoir. The temporary, permeable dam (i.e. separation means) may include multiple concentric, generally circular (or other enclosed shape) dams. The sediment and debris collect within the walls of the temporary and permeable dam (or dams); and relatively clarified water passes through the permeable dam (or dams) and re-enters the water hazard/primary reservoir. After the required sediment and debris have been removed from the water hazard/primary reservoir, the debris and sediment collected within the permeable dam structure are transported to a suitable disposal site. Alternately, in some facilities, it is possible to pump the entrained debris directly into a dump truck (or other vehicle or trailer) adjacent the water hazard/primary reservoir, wherein the dump truck bed is outfitted with a permeable membrane whereby the detritus and debris collect in the bed of the truck and the dump truck transports the accumulated detritus and debris to a disposal site without the sediment and debris having to collect on the ground. In similar fashion, the qualified diver enters the wet well and uses the hydraulic vacuum nozzle to collect sediment and debris (including algae) which tend to collect around the wet well pump intakes. The pump intake screens are cleaned at the same time.
The preferred embodiment of the present invention (with two workmen) is capable of cleaning and removing accumulated debris from one typical golf course primary reservoir and wet well in a single day, provided that the reservoir has been cleaned in the previous 6-8 months. There is no need to suspend operations of the golf course. There is no disruption of the sprinkling system since the water hazard/primary reservoir is not emptied. There is no need to temporarily rely on expensive potable water to temporarily irrigate the golf course. There is no damage done to the water hazard/primary reservoir or to the vegetation surrounding the reservoir. The water hazard/primary reservoir can be cleaned using the present invention for less than 1% of the cost of draining the reservoir and cleaning it as described above. The financial savings to the golf course operators are significant. If the present invention is utilized periodically, the golf course operator can effectively prevent future fouling of the sprinklers and pumps as well as fouling of the main system intake. Similarly, owners of decorative pools, ponds, water fountains and other recirculating water systems can benefit immensely from the present invention. The present invention avoids the necessity of draining such ponds and pools. The present invention avoids the requirement of shutting down the operation of the decorative pools, ponds and fountains and avoids the expense of having to refill those bodies of water with potable, rather expensive, city or municipal water.
Although the invention preferably is used to periodically clean primary reservoirs every six months or so, it can also be effectively used to clean reservoirs that have been neglected for years. For example, golf courses may allow debris to build up for 15-20 years. The debris may be 4-6 feet deep. The present invention can be used effectively in those situations, requiring months (and more than one year in some cases) to clean the primary reservoir. Each in such extreme cases, the present invention is more cost effective than draining the reservoir and bringing in heavy machines to clean out the debris and detritus.
The invention is lightweight and portable, but simultaneously has an enormous capacity. The vacuum nozzle generates a strong vacuum of up to 29 inches of mercury in a three inch vacuum intake or suction hose. This gives the system the capacity of removing up to 9 cubic yards (enough to fill a large dump truck) of sand or light gravel per hour using a specific, lightweight and portable embodiment of the invention. The capacity of removing sludge is about 6 yards per hour using the same embodiment.
It is therefore a primary object of the present invention to provide a method and apparatus for effectively remediating a recirculating water system for golf courses and for large scale decorative ponds and water fountains which have become fouled by sand, silt, detritus, algae and other debris.
A further object of the present invention is to provide a method and apparatus which, when used on a regular periodic basis, will effectively prevent the fouling of recirculating water system intakes, pumps and small nozzles, such as used for golf course sprinklers, fountains and decorative pools.
A further object of the invention is to provide a method and apparatus for remediating and for preventing the fouling of recirculating water systems by sand, silt, detritus, algae and other debris without requiring the system to be shutdown and without requiring the primary reservoir for such system to be drained.
A further object of the present invention is to provide a portable, hydraulic, eductor vacuum for use in removing sand, silt, algae, detritus and other debris from a primary reservoir for a recirculating water system which is capable of generating 29 inches of mercury vacuum in a three inch diameter hydraulic vacuum nozzle.
Another object of the invention is to provide a hydraulic vacuum apparatus portable in a lightweight truck and capable of removing up to 9 cubic yards per hour of sand or light gravel from a primary reservoir for a recirculating water system.
A further object of the present invention is to provide a method and apparatus for removing sand, silt, algae, detritus and other debris from the primary reservoir of a water recirculating system which can be completed in one day at a cost of less than 1 % of draining, cleaning and refilling the primary reservoir by conventional techniques described above; and which is portable in a lightweight truck.
Other objects and advantages of the invention will become apparent from the following description and the drawings wherein: